No you wouldn't. By default, zoom buttons can't guess the context of what you want zoomed. You'd rather use hardware buttons for page-up and page-down on the n900. And yes, I've remapped my browser's zoom-in and zoom-out to page-up and page-down on my n810. Now if only I had double-tap on my n810 browser...

If you don't know what double-tap is, watch qgil's demo video again. It's quickly shown before the swirling zoom. Once you have the column of interest fit-to-width, you usually only care about paging after that. But for further font-size refinement you'll have zoom menu items and client-side stylesheets.